Crosslinkable elastomer composition

ABSTRACT

A crosslinkable elastomer composition which provides a crosslinked product with improved mechanical strength and heat resistance, comprising,  
     (A) a compound having at least two crosslinkable groups represented by the formula (I):  
                 
 
     and (B) an elastomer which contains a crosslinking site capable of reacting with the crosslinkable group (I) is prepared.

TECHNICAL FIELD

[0001] The present invention relates to a crosslinkable elastomercomposition, particularly a flourine-containing crosslinkable elastomercomposition which can provide a molded article of a crosslinked rubberwith superior sealing property, mechanical strength and heat resistanceat a high temperature.

BACKGROUND ART

[0002] Because flourine-containing elastomer, especially perfluoroelasotmer which is composed mainly of tetrafluoroethylene (TFE) units,demonstrates excellent chemical resistance, solvent resistance and heatresistance, it is widely used as a sealing material and the like underharsh circumstances.

[0003] However, the characteristics in demand have become more severe astechnology advances, and in the fields of aerospace, semiconductormanufacturing devices and chemical plant, sealing property under hightemperature circumstances of at least 300° C. is desired.

[0004] In response to such demands, an approach to improve heatresistance by exercising ingenuity to the crosslinking system has beensuggested. As methods of these, a toriazine crosslinking system, using aflourine-containing elastomer with a nitrile group introduced as thecrosslinking point, to form a triazine ring in the presence of anorganic tin compound (for example JP-A-58-152041) is known. Other knowncrosslinking systems are, for example, an oxazole crosslinking system inwhich an oxazole ring is formed in the presence of bisaminophenol, (forexample JP-A-59-109546), an imidazole crosslinking system in which aimidazole ring is formed in the presence of a tetramin compound, (forexample JP-A-59-109546), and an thiazole crosslinking system in which anthiazole ring is formed in the presence of bisaminothiophenol, (forexample JP-A-8-104789). In these latter systems flourine-containingelastomer with a nitrile group is also introduced as the crosslinkingpoint.

[0005] Of these crosslinking systems, when crosslinking a nitrile groupcontaining perfluoro elasotmer with a tetramin compound, the heatresistance of the obtained molded article of the crosslinked rubber willimprove in comparison to the conventional. However, in high temperaturesexceeding 300° C., deterioration is intense in contrast to a toriazinecrosslinking system or an oxazole crosslinking system.

[0006] An object of the present invention is to provide a crosslinkableelastomer composition to produce a molded article of the crosslinkablerubber, improved especially in mechanical strength and heat resistanceat a high temperature.

[0007] Another object of the present invention is to provide a newcrosslinking agent.

DISCLOSURE OF INVENTION

[0008] The present invention relates to a crosslinkable elastomercomposition comprising (A) a compound having at least two crosslinkablegroups represented by the formula (I):

[0009] and (B) an elastomer which contains a crosslinking site capableof reacting with the crosslinkable group (I).

[0010] It has not been found that this compound (A) works as acrosslinking agent, and the compound (A) is thus a new crosslinkingagent.

[0011] As for the compound (A), a compound represented by the formula(II):

[0012] in which R¹ represents a substituted or non-substituted alkylenegroup, a substituted or non-substituted arylene group, or a grouprepresented by the formula (III):

[0013] in which R² represents —SO₂—, —O—, —CO—, a substituted ornon-substituted alkylene group,

[0014] or a single bonding, are preferably exemplified.

[0015] As for the elastomer (B), a fluorine-containing elastomer, aperfluoro elastomer in particular, which contains a nitrile group,carboxyl group and/or alkoxycarbonyl group is preferably used.

[0016] Among the compounds (A), a compound represented by the formula(IV):

[0017] in which R³ is

[0018] is a new compound which is to be included in the scope of thepresent invention.

[0019] The present invention also relates to a molded article of acrosslinked rubber, obtained by crosslinking the crosslinkable elastomercomposition.

BRIEF DESCRIPTION OF DRAWING

[0020]FIG. 1 is a chart of the infrared spectroscopic analysis of thefluorine-containing elastomer having a CN group, obtained in PreparationExample 1.

BEST MODE FOR CARRYING OUT THE INVENTION

[0021] The crosslinking system made when the crosslinkable elastomercomposition of the present invention is crosslinked is similar to animidazole crosslinking system. A conventional imidazole crosslinkingforms a crosslinking structure, for example, such as

[0022] On the other hand, in the present invention, as shown in

[0023] it is presumed that the benzimidazole ring formation without aH—N bond contributes greatly to the improvement of heat resistance.Consequently, compound (A), which functions as a crosslinking agent, isan important factor of the present invention. The following is adescription of compound (A).

[0024] In order to form the crosslinking structure, compound (A)contains at least two, preferably two to three, most preferably twocrosslinkable groups (I) represented by the formula (I).

[0025] As compound (A), a compound represented by the formula (II):

[0026] which contains two crosslinkable groups (I) is preferred from theviewpoint that synthesis is conducted with ease. R¹ and R² in theformula are as indicated above.

[0027] In the formula (III), R² is —SO₂—, —O—, —CO—, substituted ornon-substituted alkylene group,

[0028] or a single bonding.

[0029] Substituted or non-substituted alkylene group of R¹ is forexample, methylene, ethylene, butylene,

[0030] and the like.

[0031] Substituted or non-substituted arylene group of R¹ is forexample, phenylene,

[0032] and the like.

[0033] Preferred examples of the substituted or non-substituted alkylenegroup of R² in the formula (III), though not limited to these, arenon-substituted alkylene groups having 1 to 6 carbon atoms andfluoroalkylene groups having 1 to 10 carbon atoms. As the fluoroalyklenegroup,

[0034] and the like can be given. These R² are also known as examples ofbisdiaminophcnyl compounds in JP-B-2-59177 and JP-A-8-120146.

[0035] R² may be bonded to any positions of the both right and leftbenzene rings, but from the viewpoint that synthesis is conducted withease and the crosslinking reaction is easily advanced, it is preferredthat R² is so bonded as to be at a para position or meta position with—NH—group.

[0036] Preferable examples of the compound (A) are a compoundrepresented by the formula (IV):

[0037] in which R represents —SO₂—, —O—, —CO—, a substituted ornon-substituted alkylene group, or

[0038] Examples thereof, though not limited to these, are2,2-bis-[N-(2-aminophenyl)-(4-aminophenyl)]hexafluoropropane,2,2-bis-[N-(2-aminophenyl)-3-(3-aminophenyl)]hexafluoropropane,2,2-bis-[N-(2-aminophenyl)-{4-(4-aminophenoxy)phenyl}]hexafluoropropane,N,N′-di(2-aminophenyl)-4,4′-diaminodiphenyl, N,N′-di(2-aminophenyl)-4,4′diaminophenylether, N,N′-di(2-aminophenyl)-p-phenylenediamine and thelike.

[0039] The compounds (A) explained above are a new crosslinking agentwhich can provide a crosslinked product with excellent mechanicalstrength, heat resistance and chemical resistance, and in particular,well-balanced heat resistance and chemical resistance.

[0040] Furthermore, among the compounds (A), a compound represented bythe formula (IV):

[0041] in which R³ is

[0042] is a new compound.

[0043] These new compounds can be prepared by introducing nitro groupsto each corresponding 2,2-bis-(4-aminophenyl)hexafluoropropane (or2,2-bis-(3-aminophenyl)hexafluoropropane) or2,2-bis-[4-(4-aminophenoxy)phenyl]hexafluoropropane witho-fluoronitrobenzene, reducing the system in the presence of palladiumcarbon and the like.

[0044] Other compounds included in the category of the compoundrepresented by the formula (II) are described in U.S. Pat. No.3,708,439. Though purifying methods are slightly different, the processof synthesizing the compound represented by (IV) can be basicallyapplied as it is.

[0045] The following is a description of the crosslinkable elastomerwhich is the component (B).

[0046] As the crosslinkable elastomer (B), one having a crosslinkingsite capable of reacting with the crosslinkable group (I) with excellentheat resistance may be preferable, and fluorine-containing elastomerscan be given.

[0047] As the crosslinking site capable of reacting with thecrosslinkable group (I), a nitrile group (—CN), carboxyl group (—COOH),alkoxycarbonyl group (—COOR in which R is an alkyl group having 1 to 3carbon atoms) and the like can be given.

[0048] The fluorine-containing elastomer is preferably one representedby the formula (V):

X¹—[A—(Y)_(p)]_(q)—X²  (V)

[0049] or the formula (VI):

X¹—[A—(Y¹)_(p)]_(q)—[B—(Y²)_(r)]_(s)—X²  (VI)

[0050] in which X¹ and X² can be varied without any restriction bychanging the initiator or chain transfer agent for the polymerization orby modifying the terminal group, X¹ and X² may be the same or different,and each of X¹ and X² being a carboxyl group, alkoxycarbonyl group,nitrile group, iodine atom, bromine atom or sulfonate group; Y, Y¹ andY² are the same or different, and each of Y, Y¹ and Y² is a divalentorganic group containing a carboxyl group, alkoxycarbonyl group ornitrile group in the side chain; A is a fluorine-containing elastomericpolymer chain segment (hereinafter elastomeric segment A); B is afluorine-containing non-elastomeric polymer chain segment (hereinafternon-elastomeric segment B); p is an integer of 0 to 50, q is an integerof 1 to 5, r is an integer of 0 to 10, s is an integer of 1 to 3; andany one of X¹, X², Y, Y¹ and Y² is a nitrile group, carboxyl group oralkoxycarbonyl group, while Y, Y¹ or Y² may be randomly included in thesegment A or B. In addition, a fluorine-containing elastomer which has,as the crosslinking site, a carboxyl group, nitrile group, and/or alkoxycarbonyl group at the terminal of the main chain or in the branchedchain is preferable.

[0051] Examples of the elastomeric segment A are a perfluoro elastomericsegment such as a two-segment copolymer rubber represented by theformula (1):

[0052] in which m/n=95 to 50/5 to 50 (% by mole) and R_(f) is afluoropolyoxyalkyl group having 1 to 20 carbon atoms or perfluoroalkylgroup having 1 to 8 carbon atoms

[0053] or a three-segment copolymer rubber represented by the formula(2):

[0054] in which 1/m/n=95 to 35/0 to 30/5 to 35 (% by mole) and R_(f) isa fluoropolyoxyalkyl group having 1 to 20 carbon atoms or perfluoroalkylgroup having 1 to 8 carbon atoms; or

[0055] a non-perfluoro elastomeric segment such as a two-segmentcopolymer rubber represented by the formula (3):

[0056] in which m/n=85 to 60/15 to 40 (% by mole),

[0057] a three-segment copolymer rubber represented by the formula (4):

[0058] in which 1/m/n=85 to 20/0 to 40/15 to 40 (% by mole),

[0059] a three-segment copolymer rubber represented by the formula (5):

[0060] in which 1/m/n=95 to 45/0 to 10/5 to 45 (% by mole), each of Z¹,Z² and Z³ is individually a fluorine atom or hydrogen atom, R_(f) is afluoropolyoxyalkyl group having 1 to 20 carbon atoms or perfluoroalkylgroup having 1 to 8 carbon atoms,

[0061] in which 1/m=20/80 to 80/20% by mole,

[0062] in which 1/m=80/20 to 50/50% by mole,

[0063] in which 1/m/n=1 to 80/0 to 80/10 to 50% by mole, and R_(f) is asdefined above.

[0064] Examples of Y, Y¹ and Y² which introduces the crosslinking pointto the branched chain are a nitrile group-containing monomer, carboxylgroup-containing monomer and alkoxycarbonyl group-containing monomer,represented by the following formulas:

[0065] in which m is 0 to 5 and n is 1 to 8,

[0066] in which n is 1 to 4,

CF₂=CFO(CF₂)_(n)—OCF(CF₃)X³

[0067] in which n is 2 to 5,

[0068] in which n is 1 to 6,

[0069] in which n is 1 to 5, or

[0070] in which n is of 0 to 5,

[0071] [X³ being CN, COOH or COOR⁵ (in which R⁵ is an alkyl group whichhas 1 to 10 carbon atoms and may contain a fluorine atom)].

[0072] Among them, the nitrile group-containing monomer and carboxylgroup-containing monomer are usually preferred.

[0073] As for the kind of the non-elastomeric segment B, there is noparticular limitation, as long as it contains a fluorine atom and doesnot have the above elastomeric property. A suitable non-elastometricsegment may be selected depending on the desired properties or functionsof the polymer to be obtained by block copolymerization. Among thesesegments, when mechanical properties are requested, a crystallinepolymer chain segment, of which the melting point of the crystal is atleast 150° C., is preferable.

[0074] Examples of monomers constituting the non-elastomeric segment B,fluorine-containing monomers in particular, are one or at least two ofperhalo olefins such as TFE, chlorotrifluoroethylene (CTFE),perfluoro(alkyl vinyl ether) (PAVE), hexafluoropropylene (HFP),CF₂=CF(CF₂)_(p)X, (p is an integer of 1 to 10, X is F or Cl) andperfluoro-2-butene; and partially fluorinated olefins such as vinylidenefluoride, vinyl fluoride, trifluoroethylene,

CH₂=CX⁴—(CF₂)_(q)—X⁵

[0075] (each of X⁴ and X⁵ is H or F and q is an integer of 1 to 10), andCH₂=C(CF₃)₂. Furthermore, one or at least two of monomerscopolymerizable therewith, such as ethylene, propylene, vinyl chloride,vinyl ethers, carboxylate vinyl esters, and acrylic acids and acrylatesmay also be used as a component of copolymerization.

[0076] Among these, as the main component monomer, a fluorine-containingolefin alone, combination of fluorine-containing olefins, combination ofethylene and TFE, and combination of ethylene and CTFE are preferablefrom the viewpoint of chemical resistance and heat resistance. Inparticular, a perhalo olefin alone and combination of perhalo olefinsare preferable.

[0077] Specifically,

[0078] (1) VdF/TFE (0 to 100/100 to 0), particularly VdF/TFE (70 to99/30 to 1), PTFE or PVdF;

[0079] (2) ethylene/TFE/HFP (6 to 60/40 to 81/1 to 30),3,3,3-trifluoropropylene-1,2-trifluoromethyl-3,3,3-trifluoropropyl-1-ene/PAVE(40 to 60/60 to 40);

[0080] (3) TFE/CF₂=CF-R_(f) ³ (in such an amount that thenon-elastomeric property is exhibited, i.e., the amount of CF₂=CF-R_(f)³ is not more than 15% by mole; R_(f) ³ is a linear or branched fluoroor perfluoro alkyl group or a fluoro or perfluoro oxyalkyl group, whichmay contain at least one ether type oxygen atom);

[0081] (4) VdF/TFE/CTFE (50 to 99/30 to 0/20 to 1);

[0082] (5) VdF/TFE/HFP (60 to 99/30 to 0/10 to 1);

[0083] (6) ethylene/TFE (30 to 60/70 to 40);

[0084] (7) polychlorotrifluoroethylene (PCTFE);

[0085] (8) ethylene/CTFE (30 to 60/70 to 40);

[0086] and the like can be given. The unit of values in the parenthesesis % by mole. Of these, PTFE and non-elastomeric copolymer ofTFE/CF₂=CF-R_(f) ³ (R_(f) ³ is as defined above) are particularlypreferable from the viewpoint of chemical resistance and heatresistance.

[0087] In addition, as a monomer which may constitute thenon-elastomeric segment B, the above-mentioned unit Y² which createscuring site may be introduced in an amount of at most 5% by mole,preferably at most 2% by mole.

[0088] The block copolymerization of the non-elastomeric segment B canbe carried out, for example, after the emulsion polymerization of theelastomeric segment A, by exchanging the monomers to those for thenon-elastomeric segment B.

[0089] The number average molecular weight of the non-elastomericsegment B can be adjusted extensively, from 1,000 to 1,200,000,preferably from 3,000 to 400, 000.

[0090] Also, by making the proportion of perhalo olefin at least 90% bymole, in particular at least 95% by mole in the units constituting theelastomeric segment A, the block copolymerization of the non-elastomericsegment B to the elastomeric segment A is assured, and in addition, themolecular weight of the non-elastomeric segment B (polymerizationdegree) can be increased.

[0091] The terminal groups of the elastomers, i.e., X¹ and X², are notparticularly limited as mentioned above, but preferably a carboxylgroup, alkoxycarbonyl group or nitrile group. As the method ofintroducing these functional groups to the terminal group, acidtreatment mentioned later can be given.

[0092] The above fluorine-containing elastomer can be produced bypolymerization methods such as emulsion polymerization, suspensionpolymerization, and solution polymerization.

[0093] As a polymerization initiator, one which is capable of making acarboxyl group or a group capable of generating a carboxyl group (forexample, carboxyl fluoride, carboxyl chloride, CF₂OH, all of whichgenerate a carboxyl group in the presence of water) present in theelastomer terminal is preferably used. Examples are ammonium persulfate(APS), potassium persulfate (KPS) and the like.

[0094] Furthermore, a chain transfer agent which is generally used toadjust molecular weight can be used, but it is preferable that it isused as little as possible, as it decreases the ratio of groups capableof generating carboxyl groups, which are to be introduced into theterminal. However, this does not apply when the chain transfer agent iscapable of making the above group present in the elastomer terminal.When a chain transfer agent is not used, the molecular weight can beadjusted by conducting polymerization under low pressure, for exampleless than 2 MPa.G, more preferably at most 1 MPa.G. Other polymerizationconditions are not particularly limited. However, in order to obtainpolymerization products which have a carboxyl group in the terminaland/or the branched chain, without acid treatment, it is preferable thatthe pH of the polymerization system is set to a strongly acidic value ofat most pH 3.

[0095] Some of the polymerization products obtained in this way do notinclude free carboxyl groups depending on the polymerization conditions,but by subjecting to the following acid treatment, those groups can beconverted into free carboxyl groups.

[0096] As for the fluorine-containing elastomer used in the presentinvention, it is preferable to convert groups such as a metallic saltand an ammonium salt of carboxylic acid present in the polymerizationproducts into a carboxyl group by subjecting the polymerization productsto acid treatment. As methods of acid treatment, the methods of washingwith hydrochloric acid, sulfuric acid or nitric acid or setting the pHof the system after the polymerization reaction to at most pH 3 withthese acids are appropriate.

[0097] From the viewpoint of simplifying the process, it is preferablethat this acid treatment is applied as an agglomeration measure whenisolating the polymerization products from the polymerization reactionmixture by agglomeration. It is also possible to subject thepolymerization mixture to acid treatment and then isolate the polymerproducts by means of lyophilization. Furthermore, methods such asagglomeration by ultrasonic waves and the like or agglomeration bymechanical power can be adopted.

[0098] Also, it is possible to oxidize fluorine-containing elastomershaving iodine and bromine by fuming sulfic acid and then introduce acarboxyl group.

[0099] The amount of compound (A) which is a crosslinking agent ispreferable 0.1 to 10 parts by weight based on 100 parts by weight of theelastomer.

[0100] In the composition of the present invention, the usual additivesto be compounded into the crosslinkable elastomer composition such as afiller, processing aid, plasticizer and colorant may be compoundedaccording to need. One type or more than one type of commonly usedcrosslinking agents and crosslinking accelerators that differ from thoselisted above may also be compounded. Furthermore, more than two types ofelastomers may be compounded, within the range of the effects of thepresent invention not being spoiled.

[0101] The composition of the present invention can be prepared bymixing the above components by using a typical rubber-processing machinesuch as an open roll, Banbury mixer or kneader. It can also be preparedby the methods of using an internal mixer or co-coagulating from mixedemulsion.

[0102] For producing a pre-molded article from the above-mentionedcomposition, usual known methods may be employed, such as the method ofheating and compressing in a metal mold, the method of putting in aheated metal mold under pressure and the method of extruding with anextruder can be conducted. Extruded products such as a hose and electricwire are capable of maintaining its form after extrusion and therefore,the pre-molded article which is extruded without using a crosslinkingagent can be utilized as it is. It is also possible to use a pre-moldedarticle made by subjecting to crosslinking by heating with steam using acrosslinking agent. Also, when it is difficult to maintain the form ofshaped product such as an O-ring in an uncrosslinked state aftermold-releasing, it becomes possible to hold the shape by using apre-molded article which is crosslinked in advance using a crosslinkingagent.

[0103] As the crosslinking temperature, a relatively low crosslinkingtemperature (for example 150 to 230° C., preferably 170 to 200° C.)provides a crosslinked product with good properties.

[0104] The obtained crosslinked product is new also as a compound andprovides high heat resistance which could not be obtained by priorimizadole crosslinking, and in addition, superior mechanical strengthand chemical resistance.

[0105] The new crosslinked product, represented by the formula (VII):

[0106] (R¹ in the formula is as stated before) is an ultra highmolecular weight polymer which has an imizadole ring in the crosslinkingsite.

[0107] This crosslinked product has high heat resistance, superiormechanical strength and chemical resistance, and the variation over timeof the permanent compression strain at a high temperature, a standardfor evaluating sealing property, has become particularly small, and thischaracteristic is essential to sealing materials.

[0108] The crosslinked product of the present invention is effective asvarious molded articles in the fields indicated in the following Tables1,2 and 3. TABLE 1 Field of industry Sub-field of industry Final productEquipment Electrical Semi-conductor Semi-conductor CVD equipmentproduction apparatus Liquid crystal panel Dry etching equipmentproduction apparatus Plasma panel production Wet etching equipmentapparatus Oxidation and diffusion equipment Sputtering equipment Ashingequipment Cleaning equipment Ion implantation equipment TransportationVehicle Car Engine and auxiliary equipment Automatic transmission Fuelline and auxiliary equipment Aircraft Aircraft Fuel line Rocket RocketFuel line Ship Ship Fuel line Parts O (square) ring, packing, sealingmaterial, tube, roll Coating, lining, gasket, diaphragm, hose Gasket,shaft seal, valve stem seal, sealing material, hose Hose, sealingmaterial O (square) ring, tube, packing, core material of valve, hose,sealing material, diaphragm Diaphragm, O (square) ring, valve, tube,packing, hose, sealing material ditto ditto Chemical Chemical productsPlant Production line of chemicals such as pharmaceutical, agriculturalchemical, coating and resin (Petroleum) Chemicals Pharmaceuticals Plugfor chemicals Mechanical Photograph Developing machine Film developingmachine X-ray film developing machine Printing Printing machine Printingroll Coating Coating facilities Coating roll Analyzer and physical andchemical appliances Food Plant Food processing line Metal Steel makingSteel sheet processing Steel sheet processing facilities roll Lining,valve, packing, roll, hose, diaphragm, O (square) ring, tube, sealingmaterial Plug for chemicals Roll Roll Roll Roll Tube Lining, valve,packing, roll, hose, diaphragm, 0 (square) ring, tube, sealing materialRoll

[0109] TABLE 2 Field of Industry Characteristics Required ElectricalPlasma resistance, acid resistance, alkali resistance, amine resistance,ozone resistance, gas resistance, chemical resistance, cleanliness, heatresistance Transportation Heat resistance, amine resistance Heatresistance, amine resistance Fuel resistance, fuel permeability, heatresistance Fuel resistance, fuel permeability, heat resistance Fuelresistance, fuel permeability, heat resistance Fuel resistance, fuelpermeability, heat resistance Chemical Chemical resistance, solventresistance, heat resistance Chemical resistance, solvent resistance,heat resistance Cleanliness Mechanical Chemical resistance Chemicalresistance Solvent resistance Solvent resistance Food Chemicalresistance, solvent resistance, heat resistance Metal Heat resistance,acid resistance

[0110] TABLE 3 Field of industry Parts Electrical O ring and sealingmaterial for gate valve of corresponding product or equipment O ring andsealing material for quartz window of corresponding product or equipmentO ring and sealing material for chamber of corresponding product orequipment O ring and sealing material for gate of corresponding productor equipment O ring and sealing material for bell jar of correspondingproduct or equipment O ring and sealing material for coupling ofcorresponding product or equipment O ring and sealing material for pumpof corresponding product or equipment O ring and sealing material forgas controller for semi- conductor of corresponding product or equipmentO ring and sealing material for resist developing and releasingsolutions O ring and sealing material for wafer cleaning solutionDiaphragm of pump for corresponding production equipment Hose for resistdeveloping and releasing solutions Hose and tube for wafer cleaningsolution Roll for transferring wafer Lining and coating of tanks forresist developing and releasing solutions Lining and coating of tanksfor wafer cleaning solution Lining and coating of tanks for wet etchingTransportation Engine head gasket Metal gasket Crank shaft seal Camshaft seal Valve stem seal Manifold packing Oil hose ATF hose Injector Oring Injector packing O ring and diaphragm for fuel pump Fuel hoseChemical Mechanical Developing roll Developing roll Gravure roll Guideroll Gravure roll for magnetic tape production and coating line Guideroll for magnetic tape production and coating line Various coating rollsFood Metal

[0111] More specifically, the crosslinked product of the presentinvention can be used for the following semiconductor manufacturingequipment.

[0112] (1) Etching system

[0113] Dry etching equipment

[0114] Plasma etching machine

[0115] Reactive ion etching machine

[0116] Reactive ion beam etching machine

[0117] Sputter etching machine

[0118] Ion beam etching machine

[0119] Wet etching equipment

[0120] Ashing equipment

[0121] (2) Cleaning system

[0122] Dry etching cleaning equipment

[0123] UV/O³ cleaning machine

[0124] Ion beam cleaning machine

[0125] Laser beam cleaning machine

[0126] Plasma cleaning machine

[0127] Gas etching cleaning machine

[0128] Extractive cleaning equipment

[0129] Soxhlet extractive cleaning machine

[0130] High temperature high pressure extractive cleaning machine

[0131] Microwave extractive cleaning machine

[0132] Supercritical extractive cleaning machine

[0133] (3) Exposing system

[0134] Stepper

[0135] Coater and developer

[0136] (4) Polishing system

[0137] CMP equipment

[0138] (5) Film forming system

[0139] CVD equipment

[0140] Sputtering equipment

[0141] (6) Diffusion and ion implantation system

[0142] Oxidation and diffusion equipment

[0143] Ion implantation equipment

[0144] The crosslinked product of the present invention is suitable forsealing materials used under a high temperature condition of at least300° C., such as sealing material for O₂ sensor in automobile engines,aerospace equipment engines, and oil rigs.

[0145] The present invention is then explained by means of examples, butis not limited to them.

PREPARATION EXAMPLE 1

[0146] (Synthesis of CN Group-containing Elastomer)

[0147] A 3-liter stainless steel autoclave without ignition source wascharged with 1 liter of pure water, 10 g of

[0148] as an emulsifying agent and 0.09 g of disodium hydrogenphosphate.12 H₂O as a pH regulator. After the atmosphere in the systemwas replaced with nitrogen gas sufficiently to deaerate the system, theautoclave was heated to 53° C. while stirring at 600 rpm, and a mixedgas of tetrafluoroethylene (TFE) and perfluoro(methyl vinyl ether)(PMVE) (TFE/PMVE=25/75 in mole ratio) was fed so that the insidepressure became 0.78 MPa.G. Then 20 ml of an aqueous solution containingammonium persulfate (APS) in a concentration of 264 mg/ml was fed withpressurized nitrogen to initiate the reaction.

[0149] When the inside pressure lowered to 0.69 MPa.G with the advanceof the polymerization, 1.8 g of CF₂=CFOCF₂CF(CF₃)OCF₂CF₂CN (CNVE) wasfed with pressurized nitrogen. Then 4.7 g of TFE and 5.3 g of PMVE werefed with their self-pressure so that the inside pressure became 0.78MPa.G. After that, as the reaction proceeds, TFE and PMVE were fed underpressure in the same manner, and pressure increase and pressure decreasewere repeated between 0.78 MPa.G and 0.69 MPa.G. At the moment when thetotal amount of TFE and PMVE reached 70 g, 1.8 g of CNVE was fed withpressurized nitrogen.

[0150] Six hours after the initiation of the polymerization reaction,when the total amount of TFE and PMVE reached 130 g, the autoclave wascooled and an un-reacted monomer was released to prepare 1,150 g of anaqueous dispersion having a solid content of 11.3% by weight.

[0151] Then 1,000 g of the aqueous dispersion was diluted with 3,000 gof water and slowly added to 2,800 g of aqueous solution of 3.5% byweight of hydrochloric acid with stirring. After the addition, thesolution was stirred for 5 minutes and the precipitated product wasfiltrated. Further, the obtained polymer was added to 2 kg of HCFC-141b,stirred for 5 minutes and then filtrated again. After that, the steps ofwashing with HCFC-141b and filtrating were repeated four times, followedby vacuum-drying at 60° C. for 72 hours to obtain 110 g of a copolymer(nitrile group-containing elastomer).

[0152] As a result of ¹⁹F-NMR analysis, the monomer units of thecopolymer were TFE/PMVE/CNVE=59.8/39.6/0.6 in % by mole. Measurement wascarried out according to the infrared spectroscopic analysis, and thechart shown in FIG. 1 was obtained.

[0153] In the chart shown in FIG. 1, characteristic absorption of thenitrile group is found in the area of 269.2 cm⁻¹, characteristicabsorption of the carboxyl group in the area of 1774.5 cm⁻¹, and 1808.4cm⁻¹, and characteristic absorption of the OH group in the area of3556.5 cm⁻¹ and 3095.1 cm⁻¹.

SYNTHESIS EXAMPLE 1

[0154] Synthesis of(2,2-bis[N-(2-nitrophenyl)-(4-aminophenyl)]hexafluoropropane

[0155] In the followings, all the reactions were conducted under anitrogen atmosphere, and the reagents and solvents used had beendehydrated.

[0156] An autoclave was charged with 20 g (59.8 mmol) of2,2-bis(4-aminophenyl)hexafluoropropane, 15.8 ml (150.2 mmol) ofo-fluoronitrobenzene, 13.5 g (335 mmol) of magnesium oxide and 100 ml ofwater, and the temperature of the autoclave was elevated to 250° C. withstirring. The reaction was continued for 12 hours at the sametemperature. After the completion of the reaction, the system was cooledto the room temperature, and 800 ml of ethyl acetate and 300 ml of waterwere added thereto. Stirring was continued until the generated substancewas dissolved in ethyl acetate. The obtained solution was filtered withcerite, and extraction with ethyl acetate was conducted twice. Washingwas carried out with 1N-hydrochloric acid, saturated aqueous solution ofsodium hydrogen carbonate and then with saturated saline, followed bydrying with absolute magnesium persulfate, and the solvent was removedunder reduced pressure. The resulting crude product was re-crystallizedby using ethanol and 22.4 g of a red crystal of 2,2-bis[N-(2-nitrophenyl)-(4-aminophenyl)]hexafluoropropane was prepared(yeild: 65%).

[0157] The obtained product is a new compound which has the followingproperties:

[0158] Melting point: 178.3 to 179.4° C.

[0159]¹H-NMR (in CDCl₃): δ(ppm)=6.80 to 8.25 (m, 16H), 9.42 to 9.55(broad, 2H)

[0160]¹⁹F-NMR (in CDCl₃): δ(ppm)=−64.3 (s, CF₃)

[0161] IR(KBr): cm⁻¹=3350, 1606, 1578, 1510, 1348, 1258

[0162] MS m/z=576(M+)

[0163] HRMS: C₂₇H₁₈F₆N₄O₄(M+)

[0164] Calculated value=576.123

[0165] Measured value=576.122

[0166] Synthesis of2,2-bis[N-(2-aminophenyl)-(4-aminophenyl)]hexafluoropropane

[0167] 20 g (34.7 mmol) of2,2-bis[N-(2-nitrophenyl)-(4-aminophenyl)]hexafluoropropane synthesizedabove were dissolved in 200 ml of ethyl acetate. Thereto was added 1 gof 10% palladium carbon as a catalyst, and replacement with hydrogen wasthen carried out. After that, reaction was conducted at room temperatureunder a hydrogen pressure of 1.01 MPa (10 atm) for 18 hours withstirring vigorously. The obtained reaction solution was filtered withcerite to remove the catalyst, and ethyl acetate was removed underreduced pressure. The residue was re-crystallized by using achloroform-hexane mixed solution, and ethanol-water mixed solution toobtain 17 g of2,2-bis[N-(2-aminophenyl)-(4-aminophenyl)]hexafluoropropane (hereinafterpNPN-AF) in white solid (yeild: 95%).

[0168] The synthesized product is a new compound which has the followingproperties:

[0169] Melting point: 150.5 to 151.6° C.

[0170] Purity: (LC area %: silica gel column, developing solvent:acetonitrile:

[0171] 0.05% aqueous solution of phosphoric acid=80:20): 98%

[0172]¹H-NMR(in CDCl₃): δ(ppm)=6.64 to 7.26 (m, 16H), 3.00 to 3.80(broad, 4H), 5.24 to 5.35 ppm (broad, 2H)

[0173]¹⁹F-NMR(in CDCl₃): δ(ppm)=−64.7(s, CF₃)

[0174] IR(KBr):cm⁻¹=3050, 2942, 1510, 1392, 1235

[0175] MS m/z=516(M+)

[0176] HRMS: C₂₇H₂₂F₆N₄(M+)

[0177] Calculate value=516.174

[0178] Measured value=516.175

SYNTHESIS EXAMPLE 2

[0179] Synthesis of2,2-bis[N-(2-nitrophenyl)-{4-(4-aminophenoxy)phenyl}]hexafluoropropane

[0180] In the followings, all the reactions were conducted under anitrogen atmosphere, and the reagents and solvents used had beendehydrated.

[0181] An autoclave was charged with 15 g (28.9 mmol) of2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 7.62 ml (72.3 mmol)of o-fluoronitrobenzene, 6.5 g (161 mmol) of magnesium oxide and 75 mlof water, and the temperature of the autoclave was elevated to 250° C.with stirring. The reaction was continued for 12 hours at the sametemperature. After the completion of the reaction, the system was cooledto the room temperature, and 800 ml of ethyl acetate and 300 ml of waterwere added thereto. Stirring was continued until the generated substancewas dissolved in ethyl acetate. The obtained solution was filtered withcerite and extraction with ethyl acetate was conducted twice. Washingwas carried out with 1N-hydrochloric acid, saturated aqueous solution ofsodium hydrogen carbonate and then with saturated saline, followed bydrying with absolute magnesium persulfate and the solvent was removedunder reduced pressure. The resulting crude product was refined by usingsilica gel chromatography (hexane: ethyl acetate=5:1) andre-crystallized by using an ethanol-water mixed solution to obtain 15 gof2,2-bis[N-(2-nitrophenyl)-{4-(4-aminophenoxy)phenyl}]hexafluoropropanein an orange crystal (yeild: 68%).

[0182] The obtained product is a new compound which has the followingproperties:

[0183] Melting point: 117.5 to 118.1° C.

[0184]¹H-NMR(in CDCl₃): δ(ppm)=6.74 to 8.28 (m, 24H), 9.41 to 9.50(broad, 2H)

[0185]¹⁹F-NMR(in CDCl₃): δ(ppm)=−64.4 (s, CF₃)

[0186] IR(KBr):cm⁻¹=3346, 1612, 1577, 1501, 1349, 1248

[0187] MS m/z=760(M+)

[0188] HRMS: C₃₉H₂₆F₆N₄O₆(M+)

[0189] Calculated value=760.175

[0190] Measured value=760.176

[0191] Synthesis of2,2-bis[N-(2-aminophenyl)-{4-(4-aminophenoxy)phenyl}]hexafluoropropane

[0192] 15 g (19.7 mmol) of2,2-bis[N-(2-nitrophenyl)-{4-(4-aminophenoxy)phenyl}]hexafluoropropanesynthesized above were dissolved in 200 ml of ethyl acetate. Thereto wasadded 800 mg of 10% palladium carbon as a catalyst, and replacement withhydrogen was then carried out. After that, reaction was conducted atroom temperature under a hydrogen pressure of 1.01 MPa (10 atm) for 18hours with stirring vigorously. The obtained reaction solution wasfiltered with cerite to remove the catalyst, and ethyl acetate wasremoved under reduced pressure. The obtained crude product was refinedby using silica gel chromatography (hexane: ethyl acetate=2:1), andrecrystallized by using a chloroform-hexane mixed solution, andethanol-water mixed solution to obtain 12.4 g of2,2-bis[N-(2-aminophenyl)-{4-(4-aminophenoxy)phenyl}]hexafluoropropane(hereinafter EPNPN) in white solid (yeild: 90%).

[0193] The synthesized product is a new compound which has the followingproperties:

[0194] Melting point: 62.4 to 64.1° C.

[0195] Purity: (LC area %: silica gel column, developing solvent:acetonitrile: 0.05% aqueous solution of phosphoric acid=80:20): 99%

[0196]¹H-NMR(in CDCl₃): δ(ppm)=6.72 to 7.32 (m, 24H), 3.00 to 3.85(broad, 4H), 4.85 to 5.25 ppm (broad, 2H)

[0197]¹⁹F-NMR(in CDCl₃): δ(ppm)=−64.8 (s, CF₃) IR(KBr):cm⁻¹=3375, 3031,1612, 1513, 1243

[0198] MS m/z=700(M+)

[0199] HRMS: C₃₉H₃₀F₆N₄O₂(M+)

[0200] Calculated value=700.227

[0201] Measured value=700.226

SYNTHESIS EXAMPLE 3

[0202] Synthesis of(2,2-bis[N-(2-nitrophenyl)-(3-aminophenyl)]hexafluoropropane

[0203] In the followings, all the reactions were conducted under anitrogen atmosphere, and the reagents and solvents used had beendehydrated.

[0204] An autoclave was charged with 20 g (59.8 mmol) of 2,2-bis(3-aminophenyl)hexafluoropropane, 15.8 ml (150.2 mmol) ofo-fluoronitrobenzene, 13.5 g (335 mmol) of magnesium oxide and 100 ml ofwater, and the temperature of the autoclave was elevated to 250° C. withstirring. The reaction was continued for 12 hours at the sametemperature. After the completion of the reaction, the system was cooledto the room temperature, and 800 ml of ethyl acetate and 300 ml of waterwere added thereto. Stirring was continued until the generated substancewas dissolved in ethyl acetate. The obtained solution was filtered withcerite and extraction with ethyl acetate was conducted twice. Washingwas carried out with 1N-hydrochloric acid, saturated aqueous solution ofsodium hydrogen carbonate and then with saturated saline, followed bydrying with absolute magnesium persulfate and the solvent was removedunder reduced pressure. The resulting crude product was recrystallizedusing ethanol to obtain 22.4 g of2,2-bis[N-(2-nitrophenyl)-(4-aminophenyl)]hexafluoropropane in an orangecrystal (yeild: 65%).

[0205] The obtained product is a new compound which has the followingproperties:

[0206] Melting poing: 151.5 to 157.1° C.

[0207]¹H-NMR(in CDCl₃): δ(ppm)=6.75 to 8.25 (m, 16H), 9.41 to9.50(broad, 2H)

[0208]¹⁹F-NMR(in CDCl₃): δ(ppm)=−64.4(s, CF₃)

[0209] IR(KBr):cm⁻¹=3348, 1605, 1577, 1508, 1346, 1262

[0210] MS m/z=576(M+)

[0211] HRMS: C₂₇H₁₈F₆N₄O₄(M+)

[0212] Calculated value=576.123

[0213] Measured value=576.124

[0214] Synthesis of(2,2-bis[N-(2-aminophenyl)-(3-aminophenyl]hexafluoropropane

[0215] 20 g (34.7 mmol) of2,2-bis[N-(2-nitrophenyl)-(3-aminophenyl)]hexafluoropropane synthesizedabove were dissolved in 200 ml of ethyl acetate. Thereto was added 1 gof 10% palladium carbon as a catalyst, and replacement with hydrogen wascarried out. After that, reaction was conducted at room temperatureunder a hydrogen pressure of 1.01 MPa (10 atm) for 18 hours withstirring vigorously. The obtained reaction solution was filtered withcerite to remove the catalyst, and ethyl acetate was removed underreduced pressure. The residue was recrystallized by using achloroform-hexane mixed solution, and ethanol-water mixed solution toobtain 17 g of2,2-bis[N-(2-aminophenyl)-(3-aminophenyl)]hexafluoropropane (hereinaftermNPN-AF) in white solid(yeild: 95%).

[0216] The synthesized product is a new compound which has the followingproperties:

[0217] Melting point: 175.7 to 176.4° C.

[0218] Purity: (LC area %: silica gel column, developing solvent:acetonitrile: 0.05% aqueous solution of phosphoric acid): 98%

[0219]¹H-NMR(in CDCl₃): δ(ppm)=6.73 to 7.27 (m, 16H), 3.65 to3.90(broad, 4H), 5.25 to 5.35 ppm (broad, 2H)

[0220]¹⁹F-NMR(in CDCl₃): δ(ppm)=−64.8 (s, CF₃)

[0221] IR(KBr):cm⁻¹=3050, 2942, 1510, 1392, 1238

[0222] MS m/z=516(M+)

[0223] HRMS: C₂₇H₂₂F₆N₄(M+)

[0224] Calculated value=516.174

[0225] Measured value=516.174

EXAMPLE 1

[0226] A crosslinkable fluorine rubber composition was produced bymixing the fluorine-containing elastomer having a carboxyl group at theterminal and a nitrile group obtained in Preparation Example 1, the newcrosslinking agent (pNPN-AF) obtained in Synthesis Example 1, and carbonblack (Thermax N-990, available from Cancarb) which is a filleraccording to a weight ratio of 100/2.83/20 and then kneading on an openroller.

[0227] This fluorine-rubber composition was crosslinked by pressing for10 minutes at 200° C. and then subjected to a two step crosslinking inthe oven under the conditions indicated in Table 4, to prepare testsamples of crosslinked product of a 2 mm thickness and O-rings (AS568A-214). The results measuring the crosslinkability, properties undernormal conditions and permanent compression strain of the crosslinkedproduct are shown in Table 4.

[0228] (Crosslinkability)

[0229] For each crosslinkable composition, using a JSR modelcurastometer II, the vulcanization curve at the temperature indicated inTable 4 was found, and from this the lowest viscosity (v min), thehighest viscosity (v max), the induction period (T₁₀) and the optimalvulcanization time (T₉₀ ) were found.

[0230] (Properties Under Normal Conditions)

[0231] According to JIS K6301, the 100% modulus, tensile strength,tensile elongation and hardness (JIS A hardness) of the crosslinkedproduct of a 2 mm thickness was measured.

[0232] (Permanent Compression Strain)

[0233] According to JIS K6301, the permanent compression strain of theO-ring (AS-568A-2 14) after 300° C.×70 hours and 300° C.×168 hours wasmeasured.

EXAMPLE 2

[0234] An O-ring was prepared in the same manner as in Example 1, exceptthat mNPN-AF obtained in Synthesis Example 3 was used as a crosslinkingagent, kneading was conducted with the compounding ratio offluorine-containing elastomer containing nitrile/mNPN-AF/carbon black as100/2.83/20 (weight ratio) and crosslinking by pressing was conducted at200° C. for 15 minutes. Each of the properties was measured in the sameway as in Example 1 and the results are shown in Table 4.

EXAMPLE 3

[0235] An O-ring was prepared in the same manner as in Example 1 exceptthat EPNPN obtained in Synthesis Example 2 was used as a crosslinkingagent, kneading was conducted with the compounding ratio offluorine-containing elastomer containing nitrile/EPNPN/carbon black as100/3.84/20 (weight ratio) and crosslinking by pressing was conducted at200° C. for 60 minutes. Each of the properties was measured in the sameway as in Example 1 and the results are shown in Table 4. TABLE 4Example 1 2 3 Component of Composition CN-containing elastomer 100 100100 pNPN-AF 2.83 mNPN-AF 2.83 EPNPN 3.84 Carbon black 20 20 20Crosslinking property (200° C.) Lowest viscosity (N) 1.27 1.67 1.86Highest viscosity (N) 20.5 24.6 13.6 Induction period (minute) 3.5 2.18.3 Optimal vulcanization time (minute) 7.9 5.0 55 Properties undernormal condition 100 % modulus (MPa) 6.83 7.37 7.37 Tensile strength(MPa) 16.0 17.7 18.9 Elongation (%) 161 164 178 Hardness (JIS A) 74 7374 Permanent compression strain 300° C. × 70 hours (%) 37 34 47 300° C.× 168 hours (%) 59 47 64

[0236] As shown in Table 4, in the case that the crosslinking agent ofthe present invention is used, a crosslinking product superior in heatresistance and permanent compression strain can be obtained.

INDUSTRIAL APPLICABILITY

[0237] The present invention can provide a new crosslinkable elastomercomposition and a crosslinking agent, which offers a crosslinked productwith superior chemical resistance and mechanical strength and improvedheat resistance.

1. A crosslinkable elastomer composition comprising, (A) a compoundhaving at least two crosslinkable groups represented by the formula (I):

and (B) an elastomer which contains a crosslinking site capable ofreacting with the crosslinkable group (I):
 2. The composition of claim1, wherein said compound (A) is a compound represented by the formula(II):

in which R¹ represents a substituted or non-substituted alkylene group,a substituted or non-substituted arylene group, or a group representedby the formula (III):

in which R² represents —SO₂—, —O—, —CO—, a substituted ornon-substituted alkylene group,

or a single bonding.
 3. The composition of claim 2, wherein R² in theformula (III) is a non-substituted alkylene group having 1 to 6 carbonatoms or a fluoroalkylene group having 1 to 10 carbon atoms.
 4. Thecomposition of claim 3, wherein R² in the formula (III) is


5. The composition of any of claims 1 to 4, wherein said elastomer (B)contains a nitrile group, a carboxyl group and/or alkoxycarbonyl groupas the crosslinking site.
 6. The composition of any of claims 1 to 5,wherein said elastomer (B) is a fluorine-containing elastomer.
 7. Thecomposition of claim 6, wherein said fluorine-containing elastomer (B)is a perfluoro elastomer.
 8. A crosslinking agent comprising, (A) acompound having at least two crosslinkable groups represented by theformula (I):


9. The crosslinking agent of claim 8, wherein said compound (A) is acompound represented by the formula (II):

in which R¹ represents a substituted or non-substituted alkylene group,a substituted or non-substituted arylene group or a group represented bythe formula (III):

in which R² represents —SO₂—, —O—, —CO—, a substituted ornon-substituted alkylene group,

or a single bonding.
 10. The crosslinking agent of claim 9, wherein R²in the formula (III) is a non-substituted alkylene group having 1 to 6carbon atoms or a fluoroalkylene group having 1 to 10 carbon atom. 11.The crosslinking agent of claim 10, wherein R² in the formula (III) is


12. A compound represented by the formula (IV):

in which R³ is


13. A molded article of crosslinked rubber, obtained by crosslinking thecrosslinkable elastomer composition of any of claims 1 to 7.